Many of the most basic and important physical phenomena are determined by a set of “fundamental constants”, whose values are experimentally known to high accuracy. A key aspect is to know whether they are “universal constants”, i.e., whether they have always had the same value across the Universe and throughout its history. Here we made use of data from the ESPRESSO spectrograph on the Very Large Telescope (VLT) in order to determine the value of the fine structure constant 8 thousand million years ago (when the Universe was just 40% its current age) by measuring spectral transitions in a cloud at redshift z=1.15 caused by the absorption of radiation emitted by a more-distant quasar (HE0515-4414) located on the same line of sight. Through the measurement of the wavelengths of spectral transitions produced between energy levels involving the atomic fine structure, these measurements have confirmed a value for the fine structure constant that is fully consistent with Earth-based laboratory measurements, with a precision better than one part per million. This is one of the most precise and most reliable measurements of the fine structure constant at high redshift; thanks to the high sensitivity and spectral resolution power as well as the extraordinary wavelength calibration accuracy of ESPRESSO.
It may interest you
A group of astrophysicists led by Mireia Montes, a researcher at the Instituto de Astrofísica de Canarias (IAC), has discovered the largest and most diffuse galaxy recorded until now. The study has been published in the journal Astronomy & Astrophysics, and has used data taken with the Gran Telescopio Canarias (GTC) and the Green Bank Radiotelescope (GBT). Nube is an almost invisible dwarf galaxy discovered by an international research team led by the Instituto de Astrofísica de Canarias (IAC) in collaboration with the University of La Laguna (ULL) and other institutions. The name wasAdvertised on
A study led by researcher Laura Scholz, of the Instituto de Astrofísica de Canarias (IAC) has found, for the first time, observational evidence that the evolution and the properties of the galaxies are conditioned not only by the mass of the stars they contain, but aso by the effect of the dark matter halos which surround them. The results are published in the specialist journal Nature Astronomy. Dark matter comprises around 85% of all the matter in the Universe. Although ordinary matter absorbs, reflects and emits light, dark matter cannot be seen directly, which makes its detectionAdvertised on
The Director of the Starlight Foundation, and researcher at the Instituto de Astrofísica de Canarias Antonia M. Varela Pérez has contributed to a monographic edition of the prestigious journal Science dedicated to light pollution and its consequences. The starry sky has been a source of inspiration throughout human history. Astronomy has been a common element in all cultures and civilizations, and has been used to establish calendars, to navigate and discover new lands, and to drive many scientific and technical advances. The article “The increasing effects of light pollution on professionalAdvertised on